Web tensioning device



y '12,. 1953 P. A. SPERRY WEB TENSIONING DEVICE Filed May 9, 1952 ffivenzor Pia/Z 1 joerry it/T4 +W Patented May 12, 1953 UNITED STATES PATENT QFFICE I J. Q '-.2,6s7,s91- WEB TEN'SYIQNING DEVICE i Paul A. Sperry, New Haven, Conn. Application May'9, 1 952, Serial No; 286,935

slciaims. (Cl.26-63) This invention relates to a web tensioning de-" vice for tensioning a web of material such as fabric or paper transversely, or differentially tensioningthe web lon itudinally, orboth'gby means of one or more'web engaging rolls of variable longitudinal curvature. A

Longitudinallyf curved "rolls "of the -gen'eral type to which -=this invention relates are now wellknown in the textile'industry and have been employed heretofore as expanders fore-the "purpose of tensioning a fabricweb transversely or'remo've irig the wrinkles therefrom as the web travels be Combi tween various textileprocessing-stages. nations of these longitudinallycurvedxrollsihave also been used as .bow correcting devices to apply tension-tovarious'portions of a fabric web for the purpose of correcting :thef'bowed conditioner:

the weft or filler threads. While'the curvature of these presently used rollsmayzvary as. between individual rolls for different uses, to the :best of my knowledge'iall are for'medWithaipredeten,

mined curvature which is thereafter permanent andnon-variable, during the operation ;of the apparatus. x I in -The fixed'scnrvature oi prior expander 01 bowcorrecting.rolls-introduces a number of problem ziinto their ".useglwhich are noteasily overcome". For example, "in-bow correcting, a roll oi the propencurvature forgonekindoi fabric may not-be atallysuitable for another kind of fabric; filnysame maybe true; in fabric stretching and wrinklejoricrea-seremoval. In addition, a given web .of the same fabric mayvary in character-1 is'ticsbver its len thy-flue t iin qual shr nka e quently to obtain the desiredresult. This manipulationand adjustmentfnecessarily entails many work stoppages resulting in aconsiderabl'e loss of production time and man-hour's;and' consequently the" overall efficiency of the processing .operations is drastically reduced. i l t The principal purpose of ny invention therefore is to overcome many of the problemscon'ff nected with the expander and'bowcorrecting dev vices now in use by providing a; web.tensio device wherein the longitudinal curvature 'of the individual web engaging rolls may (be variedrby;

manual or... automatic: means to obtain the d sired arcuate curvature of the roll. Since the radius of curvature of the rolls or rolls can be varied, it will be apparent that a single device can be used in processing any type of web :by making "the proper adjustment for the given material and desired operation. Furthermore; the radius of curvature can be adjusted while the device is inoperation so that compensation for variations Within a particular web can easily be made with- 'out stopping the travel ofthe web. 1. The deviceio'f the invention, hereinafter described in detail; can be used in connection with most textile processing operations but is not confined to fabric processingsinceits ready adaptability permits itsuse in the processing of other typesof webs such as webs of. paper, rubberized. material or plastic, vWith the foregoing and other considerations in view, it is a primary object of my invention to; provide a web tensioning device having web en gaging rolls of variable longitudinal curvature. 5

Another important object of m invention isto' provide a web tensioning device wherein the radius of curvature of the web engaging rolls is variable betweenrelativelywide limits.

toprovide a web tensioning device wherein the companyingdrawings and from the appe'n'ded claims I'he accompanying drawings, in which likereference numerals are 'used' to. designate similar partsthroughout, illustrate one practical? embodiment for the purpose of disclosing the ins vention. Thedrawings,'however; 'should'not be talren in a limiting or "restrictive sense since itj will be apparent to those skilled in the art that; various changes in the illustrated construction" may-lbe' resorted'towithout in any Way departing from" the concept of the invention.-

In the drawings: I

cal embodiment or the devicefo f thefinvention;

' Figure l illustrates an elevation of one practif Figure 2 illustrates an elevation partly in sec tion of the web engaging roll of the device of;

i ur 1;

roll taken along line S S of Figure 1;

ak n a neh in '4,. Figure v Ei u e 5 illustrates a cross-section through a q ed: o m-int mi 4 t Aiurtherimportant' object of the invention is Figure 3 illustrates cross-section through the a-rcua-te curvature or- Figure 6 illustrates a section through a. modified form of roll bearing; and

Figure '7 illustrates an end view of the modified bearing of Figure 6.

Referring now to the drawings, a web tensioning device with a single web engaging roll I is shown in Figure 1. Roll II], which may be used as an expander to transversely tension 2. web or as a bow correcting device or for any other similar purpose, is comprised of a central,

resilient bar or axle [2, a plurality of ball or roller bearings I4, and an outer flexible sleeve I6, as will hereinafter be more fully described. The bar [2 is formed with slightly enlargedextremities l8 and 20, each extremity having a smooth bore therethrough to respectively receive one of a pair of lever arms 22, 24. Thebar is non.- rotatably secured to arms 22, 24 as at the approximate mid-points thereof by some means such as lock nuts 26 threaded on the arms.

One extremity of each-v of the lever arms 22, 24-, is adapted to be pivotally securedas at 28 and 30. to; asupporting means 32. which may be a frame of the processing equipment or a separate base member or a pair of fixed members. The opposite extremities of arms 22,, 24- carry a pair of: collar members 34, 36 which are respectively pivotedon the arms; Collars 34;, 3.6 are oppositely threaded to: receive the right and left-handscrew threads respectively of a connecting; rod 38; as. shown. Since the threaded connections between rod; 38' and each of the arms 22, 24 are oppositely arranged, rotation of the rod in one direction will cause the arms to converge while rotation. of the rod in the op-. posite direction will cause the arms to diverge. Thebar I2 is formed with a predetermined set but has suflicient resiliency sothat this curvature can be substantially varied within the elastic limit of the bar.

Since the bar ends [8, are rigidly secured to arms 22 24, any convergent or divergent movement of the arms will vary the radius of curvature of the bar, and consequently of the roll- Ill. The approximate degree of permanent curvature or set' with which bar |-2 may be formed is illust-rated in Figure 1-, andwith this degree of' curva ture arms 22", 24 be slightly convergent as shown. If rod 38 is now turned to cause arms 22*, 24 toconverge more sharply, the curvature of bar [:2 and roll IU- will be increased. For example, if arms. 22, 24 are moved to the positions indicated by phantom lines 40, the bar and roll will be forced into an approximately circulararc of smaller radius as indicated by the dash lines 42'. Conversely, if rod 38 is turned to cause arms 22, 2 to diverge from their phantom line positions, the curvature of bar I2 and: roll It! will be decreased. In this manner, the longitudinal curvature of the bar and roll can be varied at will within the elastic limit of the bar. Connecting rod 38 may be actuated. to vary the curvature of roll it] by manual means such as. a handwheel 4,4, or by some suitable power means such as a reversible electric motor, an air operated motor. or a hydraulic motor.

The roll f0 must be able to rotate freely upon the fixed bar [2 so that it can be driven by the travelling web. To this end, a series of roller bearings M or similar elements are mounted on bar l2, and a flexible sleeve l-G is fitted over the outer races 46 of' the bearings as is best shown in Figures 2 and 3*. The flexible sleeve It may be of rubber or some other material which will afford suflicient traction by the web on the roll so that objectionable slippage is prevented. The roller assembly is completed by a pair of end caps 41 which serve to keep dust and dirt from the bearings. This portion of the roll 10 is substantially conventional and can be constructed in a number of suitable ways.

The rotatable portion of roll I0 must also be able to conform to any curvature assumed by the bar 12. If the bar is of cylindrical cross section, this may be accomplished as shown in Figures 3 and 4 wherein the inner' diameter of the inner races 48 of the bearings is larger than the diameter of the bar so that there is sufiicient clear ance' taallow for whatever curvature there might be in the bar. However, as shown by the modificationof Figure 5, the bar l2 need not be of cylindrical cross. section but may be of square, rectangular, hexagonal, octagonal or almost any other cross section.

gree of difliculty involved in forming. the inner races 48 of the bearings to fit the cross section chosen. As shown in Figure 5, the bar is of rec-e tangular cross section. 50: and the inner race (8. of the bearing is formed accordingly to fit the. bar.

A further modification is. illustrated in Figures 6 and 7, wherein the inner race Q8 of the bearing is formed with a curvilinear inner surface 52 as,

shown in Figure 6. This construction permits any desired amount of curvature in the bar without any binding on thebearing. Obviously, many other suitable bearing constructions will permit the same freedom of bar action.

From the foregoing description it will be. apparent that I have provided a novel andveryuseful device for tensioning a web of any type: of tensionable material. While the. operation of but one web engaging roll has been illustrated, it will be understood that any desired number of rolls can be used for webstretching, wrinkle. and crease removal, correcting bowed conditions in the weft or filler threads of a fabric, or for anumber of other similar operations. In these operations any fabric from fine silk or rayon to heavy canvas duck maybe treated by simply adjusting the web engaging roll. to the proper curvature for the given material and desired operation. Non-fabrics such as paper, seamless rubber or plastic may be similarly treated. In addition,

since adjustment can be easily made during operation, differential conditions of stretch or shrinkage: within a particular web can be rapidly compensated for without stopping the travel of the web.

means, a pair of lever arms each pivoted at one.

end on. said support means, a resilient web en-- gaging member of variable longitudinal curvature secured between said arms, and means in engagement with the free ends of said arms to.

simultaneously move said arms towards or away:

from one another thereby causing the curvature of said web engaging member to change.

2.. In a web tension-mg device; a. pair of lever One important considera-- tion in the choice of bar cross section is the de-' arms each adapted to be pivotally mounted at one end thereof on fixed supporting means; a resilient web engaging member of variable longitudinal curvature supported by said arms; a connecting member in threaded engagement with the opposite ends of said arms, said threaded engagement between said connecting member and said individual arms being opposite to one another; and means to selectively rotate said connecting member to simultaneously move said arms towards or away from one another and thereby vary the curvature of said web engaging member.

3. In a web tensioning device; support means; a pair of lever; arms each pivoted at one end on said support means; a resilient web engaging member having adjustable longitudinal curvature and including a resilient, longitudinal- 1y curved central bar supported by said arms, a plurality of bearing members supported on said bar, and a flexible sleeve positioned over said bearing members; and means coacting with the free ends of said arms to simultaneously move said arms towards or away from one another and thereby adjust the curvature of said web engaging member.

l. An apparatus as defined in claim 3 wherein said central bar is of circular cross section, and said bearing members include inner races whose inner diameter is larger than that of said bar.

5. An apparatus as defined in claim 3 wherein said central bar is of circular cross section, and said bearing members include inner races whose inner surfaces are curvilinear.

6. In a web tensioning device; a base memher, a pair of lever arms each pivoted at one end on said base member; a resilient web engaging roll of variable longitudinal curvature, said roll including a resilient central bar non-rotatably supported by said arms at their approximate midpoints, a plurality of bearing members mounted on said bar, and a flexible sleeve mounted on said bearing members; a connecting rod having a right-hand threaded engagement with the free end of one of said arms and a left-hand threaded engagement with the free end of the other of said arms; and means to selectively rotate said connecting rod to simultaneously move the free ends of said arms towards or away from one another and thereby vary the curvature of said web engaging roll.

7. In a device for tensioning webs, support means, a lever arm having provision for its pivotal mounting on said support means, a resilient web engaging member of variable longi tudinal curvature secured with one end to said arm remote from. the pivotal mounting of the latter, means for securing the other end of said web engaging member to said support means, and means operative to swing said arm about its pivot mounting thereby causing the curvature of said web engagin member to change.

8. In a device for tensioning webs, support means, a pair of lever arms each pivotally mounted at one end on said support means, a resilient web engaging member of variable longitudinal curvature connected with its ends to said arms, respectively, remote from the pivotal mountings of the latter, and means operatively connected with said arms and operative to simultaneously move said arms toward or away from one another thereby causing the curvature of said web engaging member to change.

PAUL A. SPERRY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,393,191 Robertson Jan. 15, 1946 2,547,975 Robertson Apr. 10, 1951 2,582,280 Robertson Jan. 15, 1952 

